Rice, the Kernel of What Makes Sake, Sake

 
Rice Plant. Sake Rice. Australia Sakejpg
 

Rice is the crux of what makes sake, sake. Humans, in their never-ending quest to consume tasty things and get pissed, have long been fermenting whatever they have available to make booze. Asia has rice. Lots and lots of rice.

So, for 1000’s of years, people in Asia have been producing rice-based alcoholic drinks. China has Huangjiu and Baiju, South Korea has Cheongju and Soju and Japan has Sake, Shochu and Awamori. Pretty much every Asian country has its own equivalents, some of it distilled into spirits, some of it brewed like sake. 

Rice is the primary ingredient of sake. It cannot be made from any other grain. In Japan, there are over 300 varieties of rice, an overwhelming majority of which is short-grain, with the conveniently intuitive botanical name of Japonica Rice.

Amazing sake can be made from table rice (the sort people frequently eat), but a lot of premium sake is made from sake specific varietals. Some rice varieties like Koshi-hikari are highly respected for both eating and sake making. There are around 120 rice varietals that are approved for sake in Japan, with a dozen being responsible for a vast majority of sake production.


Sake Rice Versus Table Rice

Historically, sake was only made from the same rice that people frequently ate. Sake was made from excess rice from good harvests and was seen as a gift from the gods that allowed such bounty. Over time specific rice types were noticed to be better for making sake and subsequently cross-bred to create varieties that were even more desirable for the specific production of sake.

Sake specific varietals differ from table rice mainly in the way the individual grain is constructed. Table rice’s nutrient content (starch, protein, fat, vitamins, minerals) is spread throughout the grain relatively evenly. These non-starch nutrients provide flavour and are why they taste good.

Sake rice tends to have less non-starch nutrients, with the starch concentration in the core of the grain. This defined starchy core is called the “Shinpaku” in Japanese, which translates as the ‘White Heart’.

 
Infographic Sake Rice..png
 

Polishing

The reason the shinpaku is important is that rice used for sake brewing is almost always polished to remove some (or all) of the outer layer of non-starch nutrients. The proteins, fats, vitamins, and minerals in sake fermentation can affect the aroma’s, flavours, colours, and acidity of the sake.

This isn’t necessarily a bad thing, some of the most flavourful and interesting sakes are made from minimally polished rice.  However, the more non-starch elements present in the sake fermentation, the less control the brewery has, and the less clean and precise the sake is likely to be.

How much the rice has been polished is so influential in how the final sake often tastes that the polishing rate (Seimaibuai) is the defining factor in sake categorisation.

Polishing Rates (Seimaibuai) and Sake Categories

Junmai – is polished to a maximum of 70% (30% of the grain removed)

Junmai Ginjo – is polished to a minimum of 60% (40% of the grain removed)

Junmai Dai-ginjo – is polished to a maximum of 50% (50% of the grain removed)

Style: What Polishing Rates Usually Mean

Junmai – tend to be the most rich, robust, cereal, and savoury with the highest acidity.

Junmai Ginjo – tend to be cleaner, crisper, and more aromatic with lower acidity.

Junmai Dai-ginjo – tend to be lighter and more delicate still, with the most profuse aromatics.

These categories based on polishing rate frequently get equated to quality, with Ginjo touted as more premium than Junmai, and Dai-ginjo more premium still. This is extremely unfortunate as really these terms and classifications should only be used to differentiate and understand the stylistic variations. To say Ginjo is inherently better than Junmai is akin to saying all lager is better than all pale ale or that the longer every whisky ages in oak the better it is. I.e complete and utter nonsense.

N.B This article deals with the classification and naming conventions of “Junmai” sake. Junmai translates as “pure rice” and describes a sake that is made without any addition of extra alcohol. Junmai is the traditional style of sake (with added alcohol “aruten” sake only invented post World War II), the kind of sake we are interested in and the kind of sake we make.


Important Rice Traits in Brewing

Aside from the shinpaku being large and well-defined, these are the other factors that contribute to sake rice varietals desirability for sake brewers.

  • Size of the grain – this goes hand in hand with shinpaku in that the larger the grain is, usually the larger and more defined the shinpaku is, making polishing (and to which specific degree) easier. Sake rice grains are significantly larger (15-50%) than most table rice varieties

  • The texture of the grain – texture is important in the ease of polishing. Hard grains that don’t crack are ideal. If the grain is too hard it is likely to crack and you won’t get a uniformly polished grain. If the grain is too soft polishing to a precise degree is extremely difficult

  • Ease of growing – this is an important consideration for brewers, as whilst they rarely are involved with the growing of the rice themselves, they do want to be able to have a reliable source of rice to use for the coming season

  • Absorption rate – consistency and predictability with how much and how quickly the rice grains absorb water is highly valued as it makes brewing significantly easier

  • Melting rate – consistency and predictability with how much and how quickly the rice breaks down during fermentation is highly valued as it makes brewing significantly easier

  • Inherent character – the aromas and flavours that the rice is capable of producing in a sake fermentation.


Rice Types Influence on the Final Sake

The type of rice used in a particular sake certainly influences the final sakes aroma, texture, and taste of the sake in your glass. We will deal with some of the particularly common rice types and their common characteristics below.

It is important to understand however that the rice varietal used is often much less influential, direct, or obvious in its role in how a final sake tastes when compared with how wine grapes influence the final wine. Wine grapes have significantly more colour, aroma, flavour, and acid compounds than rice, so their inherent character influences the finished wine far more than rice does a finished sake. Decisions that the sake brewer makes when making sake tend to influence the final product more than the rice variety itself.

Different types of Sake rice

There are around 120 varieties of rice in Japan that are permitted for sake production. Of those 120, around 12 accounts for a vast majority of fields planted to sake rice varieties and sake production. Below we will go through the ones you are most likely to encounter in your sake drinking escapades.

Yamada Nishiki (Ya-ma-da Nish-key)

Main Production Area: Hyogo (South West Japan)

Production % of all sake rice grown in Japan = 30-35%

Known as the “King of Sake Rice”*, Yamada Nishiki is the most popular varietal of sake rice. It has been around since the 1930s and remains popular for many reasons. The grains are large, with a well-defined starch core (shinpaku) and don’t crack easily when polished. This means polishing Yamada Nishiki down to lower polishing ratio’s is easier and more consistent. Yamada Nishiki also tends to be the most predictable year on year in terms of how it behaves in the brewery, in terms of absorption rate, in koji making and in melting rate during fermentation.

 
A handful of polished Yamada NIshiki showing the large size of grain and uniformity possible

A handful of polished Yamada NIshiki showing the size of grain and uniformity possible

 

Sakes made from Yamada Nishiki tend towards having depth of flavour, which flows across the palate. Texturally generous but capable of delicacy and precision. Aromatically light in intensity but flavour wise I often fine a billowing rich vanilla flavour.

* The “king of sake rice” moniker has got somewhat muddied from its intended meaning. It is the “king of sake rice” for brewers, as it is the variety that is most easy and consistent to work with. It is not the “king of sake rice” in the sense that it is the rice that always makes the best sake. Cabernet Sauvignon is the worlds most planted grape variety, because it is capable of making decent wine when grown in a wide variety of environments, with a wide variety of treatments, at high yields, not because it is the necessarily always makes the best wine.

Gohyakumangoku (Go-yak-uu-man-go-koo)

Main Production Area: Niigata and neighbouring prefectures on the west coast of Japan.

Production % of all sake rice grown in Japan = 25%

The second most common sake rice. Gohyakumangoku means “five million Koku” (Koku being the traditional and still used standard measurement of sake production in Japan, equalling 180L) as this commemorates sake production exceeding this total in 1957 in Niigata, the year Gohyakumangoku was registered as a sake varietal.

With a large grain that is slightly smaller than Yamada Nishiki but with a large and well-defined shinpaku, Gohyakumangoku also behaves very well when polished. The rice tends to break down a bit less in fermentation than Yamada Nishiki, so the flavours and textures tend to be lighter.

I often find a cucumber and green melon character in sake made from Gohyakumangoku, especially on the nose.

Miyama Nishiki (Mi-ya-ma Nish-key)

Main Production Area: Nagano (Mountainous Centre of Japan) and Tohoku (Mountainous North East of Japan)

Total of Sake Specific Rice Used = 10%

The third most popular strain of sake rice in Japan was bred in 1978 in Nagano to be especially hardy in cold growing conditions, hence in popularity in its chilly place of origin and further north.

One of the hardest to differentiate inherent rice influence versus brewing traditions and preference. Sake from mountainous regions developed as richer and more robust as a) it pairs better with the preserved fish, meat and vegetables that makes up the traditional cuisine of the area and b) by the time the sake was transported to the main market of Tokyo, it has been aged for a long time and thus had a more developed flavour. This became its market differentiating point and thus this style came to define sake from the area, made from Miyama Nishiki.

So, irrespective of the true origin of the main influence, sakes made from Miyama Nishiki are commonly rich, robust, ricey, and have a gentle sweetness to them. Aromatically light but strongly flavoured and with a generous round texture.

Omachi

Main Production Area: Okayama and neighbouring South Western prefectures

Total of Sake Specific Rice Used  = 2%

The oldest known sake specific variety used today was registered as such in 1866. Omachi has an extremely large grain and shinpaku but is more prone to cracking when polishing than Yamada Nishiki. It is also harder to grow than most sake specific rice types, with its extreme height causing it to fall over easily in strong winds.

The difficulty in growing it, combined with other rice varieties being bred that were easier to work with, led to the near extinction of Omachi. In the 1970’s there were as little as 6 hectares (around 8 soccer pitches) being grown in the whole of Japan! Luckily there has been a big push to save Omachi, starting in its native Okayama prefecture and it is now the 4th most planted variety in Japan.

Sakes made from Omachi tend towards being richly textured, earthy, spicey, umami and herbal. I find a characteristic white vermouth/”gin-without-the-juniper” botanical character to sakes made from Omachi.


Outside Japan

For those brewing Sake outside of Japan, options of which rice to use are often a little more limited than within Japan.

In the USA, they are lucky enough to have some of the sake specific varietals (and the means to polish them) mentioned above grown in decent quantities, as well as table rice varieties such as Calrose, that a majority of brewers use to make good quality sake over there.

In Europe there is a lot of experimentation with local rice varieties that are most often used for Risotto or Paella, as these rice types have similar structures to sake rice and behave in a similar way.

In Australia, we are lucky enough to have a huge rice industry and a handful of varieties being grown that have Japanese heritage, such as Koshi-hikari and other varietals bred from it. No other sake rice is grown here yet, but we are hoping we can be part of helping that to change in the coming years.

How is Sake Made? A Beginners Guide: Part 2

 
A beautiful mound of white fluffy Koji, ready to make sake with

A beautiful mound of white fluffy Koji, ready to make sake with

 

Welcome back to the second part of our beginner’s guide explaining how sake is made. Start here if you haven’t already read Part 1.

We left it last time having just steamed the rice. Now we will deal with what happens with that steamed rice.

Steamed rice is destined to do one of two things; be made into Koji or added to a fermentation (either a fermentation starter or a main fermentation).


Koji Making

You will remember how important Koji is to the production of sake from part 1. Without it, there is no sake.

Why?

Koji rice is crucial in the sake making process because the koji mould it is covered in creates enzymes that convert the complex starch that you find in rice, into simple sugars. This is pivotal as yeast can’t eat starch, but it loves eating sugar. This conversion from starch to sugar is vital as when yeast feeds on sugar, it creates alcohol, aroma, and flavour (all the things we want in sake) through fermentation.

As well as allowing for the conversion of starch to sugar, Koji can create lots of amino acids (proteins) which accounts for Sake’s unique capacity for savoury umami deliciousness.

How?

Still warm steamed rice is taken into the Koji Room (Koji Muro). The Koji Room is a sealed room that is dedicated to the production of koji.

The steamed rice is laid out on a large table and sprinkled with koji spore (koji-kin) to inoculate it with the koji mould. The room is kept warm and humid to encourage the growth of the koji mould on the rice. The rice is periodically mounded together and broken up to increase or disperse temperature and ensure even koji mould coverage on the rice. This is done for between 40-48 hours.

When this process is finished you are left with rice fully inoculated with koji mould, which we now call koji. The rice should have a fluffy covering of sweet chestnut smelling koji mould.


Fermentation Starter (Shubo/Moto)

Nearly all sake produced utilises a fermentation starter, called a shubo or moto.

Why?

The purpose of a fermentation starter is to build up a healthy population of yeast and a certain level of acidity. A healthy yeast population is necessary to be strong enough to ferment the main fermentation. A certain level of acidity is required to protect the fermentation from nasty things getting in there and spoiling the batch. Not many bacteria or other microorganisms can survive in an acidic environment. Luckily for sake brewers, sake yeast is not one of them!

There are 3 commonly used starter methods:

  • Sukujo (Fast Fermentation Starter)

  • Kimoto (Traditional Starter Method)

  • Yamahai (Updated Traditional Starter Method)

All 3 use the same principle for propagating a healthy population of yeast.

  • Yeast is mixed with steamed rice, koji and water

  • The temperature is slowly raised over two weeks to allow a steady and controlled increase in the yeast population

The difference between the 3 is how they achieve the required acidity to protect the fermentation.

Sukujo Moto (Fast Fermentation Starter)

Sokujo Moto is the most modern and common method of acidifying a sake fermentation starter. Pure lactic acid is added to the shubo when the ingredients are first mixed to instantly protect it from microbial spoilage. It then takes two weeks to create the required yeast population via the temperature raising protocol we described above.

If a sake doesn’t specifically mention otherwise, it should be assumed that it was produced using a Sokujo Moto.

Kimoto (Traditional Starter Method)

Kimoto is a traditional fermentation starter method that has been used for at least 300 years. Kimoto involves keeping the shubo at a very low temperature (around 5°C) for two weeks while the mixture of steamed rice, koji and water is regularly mixed with long poles.

At this low-temperature lactic acid bacteria from the air that lands on the shubo can survive, with other bacteria not able to survive the cold. Lactic acid bacteria produce lactic acid and allows a natural population to build up in the starter. It takes around two weeks to reach the required acidity to protect the fermentation.

After these two weeks, yeast is added (a small number of producers allow wild yeast to get to work with no yeast addition). The yeast population is then allowed to build up in the same way as with Sukujo Moto, over the course of two weeks.

The mixing with long poles helps to break down the rice and oxygenate the mash, giving the lactic acid bacteria and yeast, a helping hand.

Kimoto fermentation starters take four weeks to complete, an additional two weeks compared to Sukujo moto. Two weeks to first build up the acidity, then two weeks to create the required yeast population.

Yamahai (Updated Traditional Starter Method)

Yamahai is a modern update of the Kimoto method that has been used for around 100 years. The process is similar except that the laborious pole bashing is omitted (the reasons for this will be dealt with in-depth in a later article).

In all three fermentation starter methods, the resulting mash of ingredients looks, smells, and tastes like acidic rice pudding or porridge.

 
An example of a porridgey shubo with ice cubes in to keep it extremely cold

An example of a porridgey shubo with ice cubes in to keep it extremely cold

 

Sake’s made using Sokujo moto tend to be the cleanest tasting and least acidic.

Sake’s made using Kimoto method tend to be funkier and have a prickly vibrant acidity.

Yamahai tend to be funkier still with gamey and spicy notes.


The Main Fermentation (Moromi)

Once the fermentation is complete, the next step is to start the main fermentation.

Why?

Every step so far has all been leading to this very moment, the time we get to actually make sake. How each step before this was handled and conducted will change what happens in the main fermentation, the fermentation itself is simply the realisation of every element before.

How?

Steamed rice, koji and water are added to the fermentation starter (note the yeast population has been built in the starter so no more yeast is added).

The ingredients are usually added in 3 stages over 4 days.

Stage 1 = 1/6 of total volume added

Stage 2 = Day off

Stage 3 = 2/6 of total volume added

Stage 4 = 3/6 of total volume added

The additions are done this way, so the yeast population has sufficient time to grow and be strong enough to complete the whole fermentation. If all the ingredients for the batch were added at once, the yeast could easily be overwhelmed and not become strong enough to complete fermentation.

This is also why there is a day off on the second day (poetically, as is so often the case in Japanese, referred to as “odori”, meaning to “dance”). This allows the yeast to get to grips with its new environment and start consuming the sugars created by the koji enzymes and grow stronger.

The koji sets about converting starch into sugar, and the yeast sets about eating that sugar and creating aroma’s, flavours, and alcohol.

As with the starter methods, the sake mash during the main fermentation has the appearance and consistency of rice pudding.

As with every step of the sake making process, there are many options and permutations possible, especially in terms of the temperature of the fermentation, which greatly influences the aroma’s, flavours, textures and how long the main fermentation takes.

Lower temperature = more delicate, more aromatic, lower acidity.

Higher temperature = more robust, more flavourful, higher acidity.

A range of 3-5 weeks is common with colder fermentations taking longer than warmer fermentations.

The aroma given off by the fermentation is really quite something. Profuse perfumed banana and pear are common aromas for sake fermentation.


Pressing

Why?

We need to separate the newly created delicious smelling, tasting and alcoholic liquid from the solids (rice, koji, yeast particles) so that we have sake to drink.

How?

Pneumatic Press (Yabuta)

The most common method in Japan is to use a large pneumatic press like the one pictured below. They are most commonly referred to by their manufacturer name of “Yabuta”.

With this method, the sake mash (moromi) is pumped into fine mesh sheets that are separated by balloons that fill up with air. When these balloons inflate, the pressure forces the liquid through the fine mesh, leaving behind the solids.

 
A “Yabuta” press at Fukuju in Kobe, Japan.  Each seam visible is a compartment into which mash is pumped. Air-filled balloons apply pressure to the mash, forcing the liquid away from the solids through the fine mesh, leaving the solids behind

A “Yabuta” press at Fukuju in Kobe, Japan. Each seam visible is a compartment into which mash is pumped. Air-filled balloons apply pressure to the mash, forcing the liquid away from the solids through the fine mesh, leaving the solids behind

 

This method is by far the most efficient and the level of control and precision that can be exerted is very exact.

Traditional Box Press (Fune)

Fune’s are a more traditional method of pressing. Fune’s are rectangle boxes into which small fine cotton mesh bags of mash are placed.

Bags are layered into the fune on top of each other. The pressure created by the bags on top of the ones below caused the liquid through the mesh, leaving the solids behind.

Further downward pressure is then usually exerted to press more sake out. Traditionally this was done with counter pressure beam or simply laying heavy rocks on top. Hydraulic pressing mechanisms are common nowadays.

A modern purpose-built fune with a hydraulic press at Urakasumi Brewery in Miyagi Prefecture, Japan

A modern purpose-built fune with a hydraulic press at Urakasumi Brewery in Miyagi Prefecture, Japan

The inside of Melbourne Sake’s DIY fune

The inside of Melbourne Sake’s DIY fune

Some breweries still use Fune’s for premium products, but it is increasingly rare due to the labour intensity and reduced yield compared to the increasingly precise and well controlled Yabuta’s that produce an incredibly good result.

Drip Pressing (Fukuro Shibori)

This is the oldest and most simple method of pressing.

Sake is put into fine cotton mesh bags and let to drip via only gravity.

As no external force is applied except gravity, this results in the softest and most delicate sake. Almost all high-end competition Dai-ginjo sake uses drip pressing for this reason. Some extremely expensive premium products are drip pressed and only then with a miniscule % of total production of a sake breweries total output.

 
The drip pressing set up at Zenkuro in Queenstown, New Zealand

The drip pressing set up at Zenkuro in Queenstown, New Zealand

 

Post Fermentation Options

Once the liquid sake has been pressed from its solids, we are left with an almost clear liquid. Usually, a very fine sediment remains, rendering the sake cloudy. There are a number of options a sake brewer has with how to handle this freshly pressed cloudy sake;

  • Removing sediment

  • Charcoal filtration

  • Dilution with water

  • Pasteurisation


Removing Sediment

Most sake available is clear – i.e not cloudy.

To remove the fine sediment left after pressing brewers have two main options

Sedimentation = allowing the sake to rest in a tank so the particles sink to the bottom and then pumping the now much clearer liquid sake off the top. This process is called “racking”.

Very fine Filtration = modern equipment allows for extremely precise and efficient filtration down to a specific micron. Breweries can choose a certain size of filter to achieve a certain level of sediment removal and thus a certain level of clearness.

If the Sake is Left Cloudy: Nigori

If some or all of the sediment is allowed to remain in the sake, leaving it cloudy, this is called a “nigori” sake. Nigori is a traditional style but is becoming increasingly popular in recent years and Melbourne Sake is a big fan of the nigori. We particularly the lightly cloudy examples often termed usu-nigori (usu meaning “thin”).

An example of a nigori sake

An example of a nigori sake

Nigori can range from very lightly cloudy to thick with chunky bits of rice in, like this one

Nigori can range from very lightly cloudy to thick with chunky bits of rice in, like this one


Charcoal filtration

Most sake has been charcoal filtered. Activated charcoal can be used to remove certain elements from the sake, most often colour, but also aroma, flavours, or textural elements the brewer deems undesirable. Different types of charcoal can be used to remove particular elements.

As with any kind of filtration, selectively removing only parts that are deemed negative, without removing potentially positive aspects of the sake, is practically impossible.

Charcoal filtration to remove colour is the option during the sake making process that Melbourne Sake finds most difficult to identify with. Culturally it stems from the perception that the purer the sake is, the better it is. Whilst we respect that position, it is not a position we prescribe too, in either our preferred drinking or making of sake.

If Sake isn’t Charcoal Filtered: Muroka

Muroka is the term given to sake that has not been charcoal filtered in any way. Muroka sake tends to have a characteristic and perfectly natural yellow/amber hue.


Pasteurisation

Most sake on the market has been pasteurised twice. Once just after it has been pressed and once just before it is bottled.

Pasteurisation is nothing new in the world of sake. Centuries before sake breweries understood why the process worked, they were gently heating their sake to improve stability. The process is done very gently, quickly and at a lower temperature compared to other common pasteurisations, such as milk.

This is traditionally done in the bottle in a water bath, but there are modern devices that can expedite the process.

 
Small scale bottle pasteurisation in a water bath at Melbourne Sake

Small scale bottle pasteurisation in a water bath at Melbourne Sake

 

Pasteurisation was originally done to denature the yeast and koji enzymes that are still active in the sake. Yeast and koji enzymes being still present and active can cause dramatic changes in sake. Eliminating these changes makes for a significantly more shelf-stable product that can be stored and transported with little concern of change.

If Sake Hasn’t Been Pasteurised: Nama

Nama is the term given to sake that hasn’t been pasteurised, nama meaning “fresh” or “raw”.

Unpasteurized sake tends to smell and taste fresher, with a distinctive zip and hard to describe “aliveness” that is absent from pasteurised sake. That is not to say that pasteurised sake is objectively less good, but the differences are often distinctive and pronounced.

Generally, in English speaking countries if sake is being referred to as Nama, it means it has never been pasteurised. There is however potential confusion with this as there are technically three products that contain the word “nama” in their description.

Nama-nama = sake that has never been pasteurised

Nama-chozo = sake that has been pasteurised once, before it is dispatched from the brewery

Nama-zume = sake that has been pasteurised once, straight after production but not again after

Hi-rre = is sake that has been pasteurised twice, straight after production, and again before dispatch from the brewery

Bear in mind these terms in mind if you seek clarification about how nama a nama is.

With modern understanding, technology and cold supply chain, pasteurisation is done less purely for stability, and as much as product differentiation. Most breweries release most products as both pasteurised and unpasteurised versions which can make for a really interesting comparison.

Conventional sake education dictates that sake doesn’t age particularly well and should be drunk fresh. This is touted as never truer than with nama, with claims that all nama sake must be kept refrigerated and drunk as soon as possible repeated ad infinitum.

This may very well be true for lighter, more delicate styles that are made with the intention of quick consumption. They may lose their freshness and spark if left unrefrigerated (although they may develop some interesting characteristics too). Sake’s that are built to last a long time, i.e. sakes that have intense flavours, higher acidity and alcohol can develop in incredibly interesting ways out of the fridge, especially Nama.


Dilution

Most sakes are diluted with water before release. The same water used for brewing is used for this dilution.

Most sake fermentations get up to around 18% alcohol by volume (ABV) with the legal limit in Japan being 22% ABV. A majority of sakes on the market sit around 14-16% ABV.

Just as with whisky, a little dash of water softens the palate and brings out delicate aromas and flavours that would otherwise be obfuscated.

If a Sake isn’t Diluted: Genshu

Gensu refers to sake that has had not been dilution after fermentation. Genshu sakes tend to be much more rich, robust, savoury and higher in alcohol. 


Maturation

Aside from some Nama sake that is released extremely quickly as part of its appeal, sake is matured for at least a short time before release. Most sake is rested for a minimum of 6 months to integrate and compose itself. This is similar to even the most basic white wine.

Some sake is matured for much longer before release. Sake that is aged for many years and takes on especially pronounced aged characteristics (nuts, caramel, roasted chestnuts, spices, cooked mushrooms) is often termed “koshu”.

Aside from time, the choice of vessel can lend a difference to finished sake. Stainless steel or coated enamel tanks is the most common, but some are aged in bottle.

Some sake is aged in Kioke, large format Japanese cedar barrels. Sake takes on the flavour of the wood very readily so most sakes are aged this way tend to be aged for a matter of weeks and months, rather than the years in a barrel that some wine or spirits do. Sake that has spent time aging in cedar are termed taru-zake.

 
A small kioke that can be used for maturation of taru-zake

A small kioke that can be used for maturation of taru-zake

 

And finally after all of that you have a bottle of sake in your hands ready to drink! Hurray.

We hope you found this guide to how sake is made illuminating.

As always – any questions, about anything, please get in touch via one of the options below.

Cheers,

Melbourne Sake

How is Sake Made? A Beginners Guide: Part 1

 
A common sight in sake breweries. These buckets can be filled with ice or warm water and placed in tanks to control fermentation temperature

A common sight in sake breweries. These buckets can be filled with ice or warm water and placed in tanks to control fermentation temperature

 

One of the things Melbourne Sake loves so much about sake is that it is fundamentally a simple thing that can be unbelievably complex. There is boundless complexity in its history, production, and in your glass.

Sake is made with only 4 ingredients: Rice, Koji, Yeast and Water but can give rise to a huge array of possible aroma’s, flavours, textures, and colours. The ingredients used, how they are used, and how they interact with each other, all integrally contribute to these elements in a finished sake. Minuscule changes are capable of making monumental differences.

This is a beginner’s guide, a Sake 101 if you will, to try and explain this millennia old, fascinating, and endlessly complicated brewing process as simply as possible. To make it more digestible we have broken it down into two parts. This is part 1.


Ingredients

Rice

All sake is made from rice. There are 1000’s of varieties of rice all over Asia. The rice is Japan is almost all short-grain used both for eating and making sake. Some amazing sake is made from table rice (the kind people frequently eat) but most is made from sake specific rice varietals.  

Sake specific varietals differ from table rice mainly in the way the individual grain is constructed. Table rice’s nutrient content (starch, protein, fat, vitamins, minerals) is spread throughout the grain relatively evenly. These non-starch nutrients provide flavour and is why tables rice tastes good.

Sake rice tends to have the starch concentrated in the core of the grain, with the other nutrients more concentrated around the outside of the grain. This defined starchy core is called the “Shinpaku” in Japanese, which translates as the ‘White Heart’.

 
Sake Rice Polishing Rate. Seimaibuai. Sake Rice Grain.png
 

The reason this is important is because rice used for sake brewing is almost always polished to remove some (or all) of the outer layer of non-starch nutrients. The proteins, fats, vitamins, and minerals in a fermentation can affect the aroma’s, flavours, colours, and acidity of the sake. This isn’t necessarily a bad thing, some of the most flavourful and interesting sakes are made from minimally polished rice.  However, the more non-starch elements present in the sake fermentation, the less control the brewer has.

When making incredibly delicate and precise sake (Ginjo styles), being able to control the fermentation and thus the character in the final sake is the most important thing. When making rich robust sake (Junmai styles), some control can be given over to allow for the development of rich, savoury and umami flavours encouraged by the proteins, fats and vitamins and minerals.

Koji-kin and Koji

Every sake brewers and sake geeks favourite subject. Koji-kin is the reason making sake is possible. And Soy Sauce. And Miso. And Mirin. Anndddddddd Shochu. And anything else distinctly Japanese and fermented that you care to think of. Koji-kin is the official mould of Japan for a reason.

Koji-kin is a kind of fungus (Apergillus Oryzae) that likes to grow on rice. Sake brewers sprinkle spores of Koji-kin fungus onto steamed rice to purposefully inoculate the grains of rice with Koji-kin.

Rice that has had koji-kin grown on it, is called koji.

These terms often (and understandably given their similarly) get mixed up and confused so for clarities sake to reiterate;

Koji-kin = the fungus spores of Aspergillus Oryzae

Koji = the rice that has had koji-kin grown on it

 
Koji rice showing a white fluffy covering of koji mould

Koji rice showing a white fluffy covering of koji mould

 

Koji rice is crucial in the sake making process because the koji mould it is covered in creates enzymes that convert the complex starch that you find in rice, into simple sugars. This is pivotal as yeast can’t eat starch, but it loves eating sugar. This conversion from starch to sugar is vital as when yeast feeds on sugar, it creates alcohol, aroma, and flavour (all the things we want in sake) through fermentation.

As well as allowing for the conversion of starch to sugar, Koji can create lots of amino acids (proteins) which accounts for Sake’s unique capacity for savoury umami deliciousness.

Yeast

Yeast causes fermentation by feeding on sugars. This process of yeast feeding on sugar creates three excellent things when it comes to making sake; alcohol, aroma, and flavour.

Naturally occurring yeasts are all around us and has been used in one form or another to make bread, beer, and wine for millennia. As with most other fermented beverages, using ambient “wild” yeast to ferment sake was the only option until the 19th century. Some artisanal craft breweries in Japan do still rely on ambient yeast but it is more common to use laboratory cultivated, specifically selected yeast strains these days – as it is with modern beer, spirits, and wine production.

There is a wide array of these cultivated yeasts available, with new ones being isolated, and old ones rediscovered all the time. The type of yeast used drastically alters the aromas and flavours found in Sake and is a rabbit hole of potential.

Water

By far the most voluminous ingredient in sake production. Around 80% of a finished sake is water. Given this, the composition of the water used clearly will make a huge difference to the production process and finished sake.

Specifically the mineral content of the water makes a huge impact on style. Water is often described as being somewhere on the spectrum of soft to hard based on it’s mineral content.

Hard water = High mineral content 

Soft water = Low mineral content

Calcium and magnesium are the minerals measured to determine water hardness.

Harder water leads to a faster fermentation as the yeast are encouraged and strengthened by the high mineral nutrient content. Hard water sake tends to be drier, stronger in alcohol and taste as the fermentation is faster and stronger, and uses up more sugars.

Soft water leads to soft sake. Soft water causes slower more gentle fermentations as the yeast isn’t being fed as much by the mineral content. This soft and gentle fermentation tends to lead to softly textured and flavoured sake’s, with more sweetness, as the slower fermentation doesn’t use up as many sugars.


Sake Making Process

Polishing

Once the rice is harvested in Autumn, the very first brewing process is to polish the rice.

Why?

As explained above the purpose of polishing the rice is to remove the non-starch nutrients from the grain, to give the sake brewer more control over the fermentation.

How?

Carefully polishing away the outer layer of rice without breaking or cracking the grains requires specialised machines that are used exclusively for the polishing of sake rice. The machines are extremely expensive and often ginormous.

Because of this, most breweries do not polish their own rice and it is done by the huge mega breweries who can afford such machinery, or centralised contract milling companies.

 
This is the smallest polishing machine you can get. Most are 10x the size

This is the smallest polishing machine you can get. Most are 10x the size

 

Washing

As most breweries don’t polish their own rice, the first step within most breweries is to wash the rice.

Why?

Rice is washed to remove any particles that remain on the outside of the grains. Most of these particles are the rice flour (nuka) that remain on the grain after polishing. The rice flour needs to be removed from the grain as when it comes to steaming the rice, the tiny particles of starch will melt and act like glue when it cools, making the grains stick together.

Stuck together clumps of rice are no good for brewing as they are uneven and inconsistent in size and thus behave differently and less predictably than separate individual grains. Washing therefore is a critical step to help achieve individual rice grains and allow for consistency and controllability throughout the entire process.  

How?

Almost all breweries have purpose made but simple rice washers like the one pictured below. Rice is dumped in the top, water is pumped in at high enough pressure to create a vigorous swirl, and the rice gets a good old washing.

Some breweries (such as Melbourne Sake) use a simple hand washing equivalent for some or all of their products. In this method, rice is put in a fine mesh bag and swilled around in water by hand.

Typical rice washing times are between 1 and 2 minutes.

 
A typical rice washer seen in almost every brewery around the world. They are often referred to simply by the manufacturers name “Woodson”.

A typical rice washer seen in almost every brewery around the world. They are often referred to simply by the manufacturers name “Woodson”.

 

Soaking

After the rice has been washed, the rice is soaked in water to increase its moisture content.

Why?

Increasing the moisture content is important as it assists in the next step, steaming. The reason rice is steamed is to break down or “gelatinise” the starch present in the rice grain. Soaking the rice to increase its moisture content means that starch is gelatinised more quickly and effectively during steaming. 

Brewers aim for a specific % of moisture intake. Different desired outcomes will require different percentages of absorption, but a 30-33% absorption rate is common.

How?

Soaking can be done in bulk in large plastic or metal containers. This method is usually for inexpensive, less premium products.

More commonly, the rice is placed in fine mesh cotton bags that can hold 5-10kg with a zip (not dissimilar to domestic laundry bags). After washing, the rice is usually put straight into a small container pre-filled water for a pre-designated amount of time to achieve a certain absorption rate. This normally takes between 5-20 minutes depending on rice type, polishing rate, water temperature and the ambient conditions.

 
The lo-fi soaking apparatus we use at Melbourne Sake

The lo-fi soaking apparatus we use at Melbourne Sake

 

Steaming

The soaked rice is usually left overnight before being steamed first thing in the morning.

Why?

As described above, steaming is done to break down or “gelatinise” the starch. This helps the koji-kin grow better on the rice during Koji Making (see Part 2 of this article for further details) and for the enzymes created by the koji rice to convert that gelatinised starch into sugars in the fermentation starter and main fermentation.

How?

In Japanese breweries, steaming is done in large purpose-built stainless-steel steamers called Koshiki. They are a bit like giant versions of domestic kitchen steamers in that they have two compartments and a meshed separator. The rice is placed in the top compartment and water is either directly boiled underneath or steam is generated in a boiler and piped in. Most Koshiki’s can hold 1-3 tonnes of rice at a time.

Outside of Japan such specialised equipment is hard to come by and thus brewers have to be creative. We use a large stock pot with a false bottom we have fashioned from a BBQ grill. An idea we borrowed from Dave Joll at Zenkuro in Queenstown, NZ.

The steaming process takes between 45-60 minutes.

A typical Koshiki in a Japanese Brewery. Can steam 3 tonnes of rice at a time.

A typical Koshiki in a Japanese Brewery. Can steam 3 tonnes of rice at a time.

Melbourne Sake’s DIY current steaming set up.. Can steam 30KG at a time.

Melbourne Sake’s DIY current steaming set up.. Can steam 30KG at a time.

Thus concludes Part 1. To read Part 2 please click here.

As always – any questions, about anything, please get in touch via one of the options below.

Cheers,

Melbourne Sake